Surface modes and extinction properties of a doubly dispersive spherical shell

The dispersion curves of the surface electrostatic and magnetostatic modes of a spherical shell which is made of a material with dispersive permittivity and permeability, and which has a negative refractive index over a frequency band, are calculated. Both the case of a dielectric core and that of a metallic core are treated. The extinction properties of the shell are derived, and the dependence of the extinction spectrum on the geometrical parameters is investigated.